On Floating Bodies, ^e, 33 



liquid body with a greater degree of velocity than the fluid, 

 under the circumstances already enumerated, can attain. 



Captain B. savs, this greater progressive motion in the 

 floating body is not owing to a iDore rapid under-current. 

 I think not, but to the causes already assigned. Captain 

 B. says, the surface of the ocean is an incfmed plane. I 

 have stated in some letters several months ago in the Phi- 

 losopliical Magazine, that the surface of the ocean, owing 

 to the attraction of gravitation and its laws, and to the im- 

 pression of the winds, &c., consists of an infinity of in- 

 clined planes, or ascents and descents. 



No collision could take place between a heavier and 

 lighter barge or body passing London bridge wiih the ebb 

 of the tide, let them be ever so near, provided the heavier 

 body were foremost, because on its descent it will, from 

 its greater wcipht, acquire a momentum which will carry it 

 on more rapidly than the lighter body ; but if the lighter 

 body were foremost and very near, it might be overtaken, 

 and a collision take place. 



When the wind blows strong into any bay, or against 

 an embayed coast, there must be an under-current, because 

 the wind prevents the return of the accumulated water 

 along the surface. All pressure on bodies floating with 

 streams must, whether the pressure be perpendicular oi- 

 oblique, increase their progress : — if the pressure be perpen- 

 dicular, it adds to tlie weight, and consequently to their 

 power of overcoming resistance on the part of the fluid : if 

 the pressure be obli(|uc, and in direction of the motion^ it 

 will, besides increasmg the weight, give impu'se. 



The reason why ships at sea that are deeply loaded make 

 less progress on a voyage than those that are lighter, and 

 uhich seems to be in contradiction to what was last stated, 

 seems to me to arise from the following cause : that is, 

 that what they gain by their gravity over a lighter vessel in 

 descending from the top of the wave or inclined plane, they 

 lose in ascending the next; for it is manifest that the sur- 

 face of the ocean consists of innumerable inclined pla^ies, 

 or ascents and descents; but in a river or running si ream 

 thf? whole progress is on a descent. 



Two pieces of wood of the same kind and of the same 

 weight, but of difterent shapes, the one, for instance, a cy- 

 linder with all its transverse diameters equal, the other of a 

 conical form, with its transversediametcrsorlines all unequal, 

 would, in my opinion, differ considerably in their progress 

 in the same fluid, the cone making greater way than the 

 cylinder; and to this I presume it iiiay be principally at- 

 Vol. ^5. No. 141. Jan, 1810. C tributcd 



